3-(diloweralkanoyl) methylphthalides



United States Patent C 2,938,910 3-(DILOWERALKANOYL)METHYLPHTHALIDESDonald D. Wheeler and David C. Young, Midland, Mich., assignors to TheDow Chemical Company, Midland, Mich., a corporation of Delaware NoDrawing. Filed Sept. 19, 1956, Ser. No. 610,870 4 Claims. (Cl. 260-3433)This invention is concerned with phthalide s having the formula CORCOCH:

to produce the desired phthalide and Water of reaction.

The terms phthalaldehydic acid and S-hydroxyphthalide" refer to acompound having the structure Phthalaldehydic acid is as having thestructure often represented in the literature CHO COOH

However, the acid employed in this invention and prepared as hereinafterdescribed exists almost entirely in the 3-hydroxyphthalide form asobserved from a study of its infrared absorption spectrum. Infrared dataalso indicate the products of the present invention to exist in thephthalide form.

In the synthesis good results are obtained when substantially equimolarproportions of the reactants are employed. The reaction takes placesmoothly in the temperature range of from 90 to 130 C. Solvents such asbenzene and toluene may be employed as reaction medium, if desired.

In carrying out the reaction, phthalaldehydic acid and the appropriatediketone are mixed together and heated from 0.5 to 4 hours. Aftercompletion of the heating, the mixture is cooled somewhat and pouredinto water to 2,938,910 Patented May31, 1960i precipitate the desiredproduct. The resulting mixture is then cooled to from to 25 C. If theproduct is a solid, it is separated from the mixture by filtration andpurified by conventional means. If the product is a liquid, it isextracted from the mixture with benzene and 7 the benzene extract heatedto distill the benzene and reas residue. the invention but are cover thedesired phthalide product The following examples illustrate not to beconstrued as limiting.

Example 1.-3-Diacetylmezhylphthalide 4 COOH:

CHCH

C ll

Example 2.3-(J-acetyl-I-propionyl) methylphthalide COCH:

CH-CH COOHQOH) Example 3 .-3- (l -acetyl-J -butyryl)menhylphthalide C OCHI CH-CH 64 grams (0.5 mole) of 2,4-heptanedione and grams (0.5 mole)of phthalaldehydic acid are mixed together and heated under reflux for 2hours. After completion of the heating, the mixture is cooled to aboutC. and poured into 500 milliliters of Water to precipitate the desiredproduct as an oil. The resulting mixture is extracted with benzene andthe benzene extract heated to distill the solvent and to obtain asresidue a 3-( l-acetyl-lbutyryl)met-hylphthalide product having amolecular weight of 260.

In a similar manner the following phthalidles are prepared:

3-(1-acetyl-1-isobutyryl)methylphthalide having a mo- COCHICHICHI ing amolecular weight of 274 by the reaction of phthalaldehydic acid with 6-methyl-2 ,4heptanedione.

I The products of this invention are useful as parasiticides. They areparticularly valuable for the control of bacterial and fungal organisms.In a representative operation, 3-(diacetylmethyDphthalide was added tobacteriological media to give a concentration of 0.05 percent and themedia inoculated with Staphylococcus aureus and Rhizopus nigricans andincubated at 30 C. for 4 days. At the end of this period, completeinhibition of growth of the organisms was observed.

The products are also'useful as insecticides. In a representativeoperation, substantially complete controls were obtained whencockroaches. (Periplaneta americana) were contacted with a toxiccomposition containing 0.24 gram of 3-diacetylmethyl(phthalide) in 100milliliters of aqueous dispersion.

The phthalaldehydic acid employed in this invention may be prepared byfirst photochlorinating o-xylene to obtaina,a,a,a,a-pentachloro-o-xylene by passing chlorine gas into o-xylenewhile illuminating with sunlamps. The 1 resulting chlorinated o-xyleneis then heated with an aqueous hydrochloric acid solution to obtainphthalaldehydic acid as more fully disclosed in US. Patent 2,748,162.

The diketones employed in this invention may be prepared by acylatingacetone with an appropriate acid anhydride in the presence of a basic orboron trifluoride catalyst.

We claim: 7

1. A phthalide having the formula COR err-03 References Cited in thefile of this patent Beilsteins Handbuch der Org. Chemie, vol. 17, pp.571, 574 and 576.

1. A PHTHALIDE HAVING THE FORMULA